Mapping between volume data block and file data block system and method

ABSTRACT

A method, computer program product, and computer system for receiving, at a computing device, an I/O request directed to a compressed data portion of a storage system. It may be determined whether the I/O request includes one of a first portion of information and a second portion of information. An address of the compressed data portion may be obtained via downward mapping if the I/O request includes the first portion of information. The address of the compressed data portion may be obtained via upward mapping if the I/O request includes the second portion of information. The I/O request may be executed at the compressed data portion.

BACKGROUND

Generally, with the increasing amounts of information being stored, itmay be beneficial to efficiently store and manage that information.While there may be numerous techniques for storing and managinginformation, each technique may have tradeoffs between reliability andefficiency.

BRIEF SUMMARY OF DISCLOSURE

In one example implementation, a method, performed by one or morecomputing devices, may include but is not limited to receiving, at acomputing device, an I/O request directed to a compressed data portionof a storage system. It may be determined whether the I/O requestincludes one of a first portion of information and a second portion ofinformation. An address of the compressed data portion may be obtainedvia downward mapping if the I/O request includes the first portion ofinformation. The address of the compressed data portion may be obtainedvia upward mapping if the I/O request includes the second portion ofinformation. The I/O request may be executed at the compressed dataportion.

One or more of the following example features may be included. The firstportion of information may include a file system ID, an inode number,and a file block offset. Obtaining the address of the compressed dataportion via downward mapping may include locating a mapping pointer thatpoints to compression Virtual Block Metadata, wherein the compressionVirtual Block Metadata may include a ZipHeader with a plurality of fileoffsets. Obtaining the address of the compressed data portion viadownward mapping may further include obtaining at least one file offsetof the plurality of file offsets, and at least one byte offset. Thesecond portion of information may include an address of a compresseddata block in a data volume. Obtaining the address of the compresseddata portion via upward mapping may include obtaining a compressionVirtual Block Metadata address from a block metadata in which thecompressed data portion resides. Obtaining the address of the compresseddata portion via upward mapping may further include verifying a mappingto the compressed data portion using an inode number and file blockoffset pair.

In another example implementation, a computing system may include one ormore processors and one or more memories configured to performoperations that may include but are not limited to receiving an I/Orequest directed to a compressed data portion of a storage system. Itmay be determined whether the I/O request includes one of a firstportion of information and a second portion of information. An addressof the compressed data portion may be obtained via downward mapping ifthe I/O request includes the first portion of information. The addressof the compressed data portion may be obtained via upward mapping if theI/O request includes the second portion of information. The I/O requestmay be executed at the compressed data portion.

One or more of the following example features may be included. The firstportion of information may include a file system ID, an inode number,and a file block offset. Obtaining the address of the compressed dataportion via downward mapping may include locating a mapping pointer thatpoints to compression Virtual Block Metadata, wherein the compressionVirtual Block Metadata may include a ZipHeader with a plurality of fileoffsets. Obtaining the address of the compressed data portion viadownward mapping may further include obtaining at least one file offsetof the plurality of file offsets, and at least one byte offset. Thesecond portion of information may include an address of a compresseddata block in a data volume. Obtaining the address of the compresseddata portion via upward mapping may include obtaining a compressionVirtual Block Metadata address from a block metadata in which thecompressed data portion resides. Obtaining the address of the compresseddata portion via upward mapping may further include verifying a mappingto the compressed data portion using an inode number and file blockoffset pair.

In another example implementation, a computer program product may resideon a computer readable storage medium having a plurality of instructionsstored thereon which, when executed across one or more processors, maycause at least a portion of the one or more processors to performoperations that may include but are not limited to receiving an I/Orequest directed to a compressed data portion of a storage system. Itmay be determined whether the I/O request includes one of a firstportion of information and a second portion of information. An addressof the compressed data portion may be obtained via downward mapping ifthe I/O request includes the first portion of information. The addressof the compressed data portion may be obtained via upward mapping if theI/O request includes the second portion of information. The I/O requestmay be executed at the compressed data portion.

One or more of the following example features may be included. The firstportion of information may include a file system ID, an inode number,and a file block offset. Obtaining the address of the compressed dataportion via downward mapping may include locating a mapping pointer thatpoints to compression Virtual Block Metadata, wherein the compressionVirtual Block Metadata may include a ZipHeader with a plurality of fileoffsets. Obtaining the address of the compressed data portion viadownward mapping may further include obtaining at least one file offsetof the plurality of file offsets, and at least one byte offset. Thesecond portion of information may include an address of a compresseddata block in a data volume. Obtaining the address of the compresseddata portion via upward mapping may include obtaining a compressionVirtual Block Metadata address from a block metadata in which thecompressed data portion resides. Obtaining the address of the compresseddata portion via upward mapping may further include verifying a mappingto the compressed data portion using an inode number and file blockoffset pair.

The details of one or more example implementations are set forth in theaccompanying drawings and the description below. Other possible examplefeatures and/or possible example advantages will become apparent fromthe description, the drawings, and the claims. Some implementations maynot have those possible example features and/or possible exampleadvantages, and such possible example features and/or possible exampleadvantages may not necessarily be required of some implementations.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an example diagrammatic view of a mapping process coupled toan example distributed computing network according to one or moreexample implementations of the disclosure;

FIG. 2 is an example diagrammatic view of a computer of FIG. 1 accordingto one or more example implementations of the disclosure;

FIG. 3 is an example diagrammatic view of a storage target of FIG. 2according to one or more example implementations of the disclosure;

FIG. 4 is an example diagrammatic view of a file system layout accordingto one or more example implementations of the disclosure;

FIG. 5 is an example flowchart of a mapping process according to one ormore example implementations of the disclosure;

FIG. 6 is an example diagrammatic view of an example storage systemlayout according to one or more example implementations of thedisclosure; and

FIG. 7 is an example diagrammatic view of an example storage systemlayout according to one or more example implementations of thedisclosure.

Like reference symbols in the various drawings indicate like elements.

DETAILED DESCRIPTION

System Overview:

In some implementations, the present disclosure may be embodied as amethod, system, or computer program product. Accordingly, in someimplementations, the present disclosure may take the form of an entirelyhardware implementation, an entirely software implementation (includingfirmware, resident software, micro-code, etc.) or an implementationcombining software and hardware aspects that may all generally bereferred to herein as a “circuit,” “module” or “system.” Furthermore, insome implementations, the present disclosure may take the form of acomputer program product on a computer-usable storage medium havingcomputer-usable program code embodied in the medium.

In some implementations, any suitable computer usable or computerreadable medium (or media) may be utilized. The computer readable mediummay be a computer readable signal medium or a computer readable storagemedium. The computer-usable, or computer-readable, storage medium(including a storage device associated with a computing device or clientelectronic device) may be, for example, but is not limited to, anelectronic, magnetic, optical, electromagnetic, infrared, orsemiconductor system, apparatus, device, or any suitable combination ofthe foregoing. More specific examples (a non-exhaustive list) of thecomputer-readable medium may include the following: an electricalconnection having one or more wires, a portable computer diskette, ahard disk, a random access memory (RAM), a read-only memory (ROM), anerasable programmable read-only memory (EPROM or Flash memory), anoptical fiber, a portable compact disc read-only memory (CD-ROM), anoptical storage device, a digital versatile disk (DVD), a static randomaccess memory (SRAM), a memory stick, a floppy disk, a mechanicallyencoded device such as punch-cards or raised structures in a groovehaving instructions recorded thereon, a media such as those supportingthe internet or an intranet, or a magnetic storage device. Note that thecomputer-usable or computer-readable medium could even be a suitablemedium upon which the program is stored, scanned, compiled, interpreted,or otherwise processed in a suitable manner, if necessary, and thenstored in a computer memory. In the context of the present disclosure, acomputer-usable or computer-readable, storage medium may be any tangiblemedium that can contain or store a program for use by or in connectionwith the instruction execution system, apparatus, or device.

In some implementations, a computer readable signal medium may include apropagated data signal with computer readable program code embodiedtherein, for example, in baseband or as part of a carrier wave. In someimplementations, such a propagated signal may take any of a variety offorms, including, but not limited to, electro-magnetic, optical, or anysuitable combination thereof. In some implementations, the computerreadable program code may be transmitted using any appropriate medium,including but not limited to the internet, wireline, optical fibercable, RF, etc. In some implementations, a computer readable signalmedium may be any computer readable medium that is not a computerreadable storage medium and that can communicate, propagate, ortransport a program for use by or in connection with an instructionexecution system, apparatus, or device.

In some implementations, computer program code for carrying outoperations of the present disclosure may be assembler instructions,instruction-set-architecture (ISA) instructions, machine instructions,machine dependent instructions, microcode, firmware instructions,state-setting data, or either source code or object code written in anycombination of one or more programming languages, including an objectoriented programming language such as Java®, Smalltalk, C++ or the like.Java® and all Java-based trademarks and logos are trademarks orregistered trademarks of Oracle and/or its affiliates. However, thecomputer program code for carrying out operations of the presentdisclosure may also be written in conventional procedural programminglanguages, such as the “C” programming language, PASCAL, or similarprogramming languages, as well as in scripting languages such asJavascript, PERL, or Python. The program code may execute entirely onthe user's computer, partly on the user's computer, as a stand-alonesoftware package, partly on the user's computer and partly on a remotecomputer or entirely on the remote computer or server. In the latterscenario, the remote computer may be connected to the user's computerthrough a local area network (LAN) or a wide area network (WAN), or theconnection may be made to an external computer (for example, through theinternet using an Internet Service Provider). In some implementations,electronic circuitry including, for example, programmable logiccircuitry, field-programmable gate arrays (FPGAs) or other hardwareaccelerators, micro-controller units (MCUs), or programmable logicarrays (PLAs) may execute the computer readable programinstructions/code by utilizing state information of the computerreadable program instructions to personalize the electronic circuitry,in order to perform aspects of the present disclosure.

In some implementations, the flowchart and block diagrams in the figuresillustrate the architecture, functionality, and operation of possibleimplementations of apparatus (systems), methods and computer programproducts according to various implementations of the present disclosure.Each block in the flowchart and/or block diagrams, and combinations ofblocks in the flowchart and/or block diagrams, may represent a module,segment, or portion of code, which comprises one or more executablecomputer program instructions for implementing the specified logicalfunction(s)/act(s). These computer program instructions may be providedto a processor of a general purpose computer, special purpose computer,or other programmable data processing apparatus to produce a machine,such that the computer program instructions, which may execute via theprocessor of the computer or other programmable data processingapparatus, create the ability to implement one or more of thefunctions/acts specified in the flowchart and/or block diagram block orblocks or combinations thereof. It should be noted that, in someimplementations, the functions noted in the block(s) may occur out ofthe order noted in the figures. For example, two blocks shown insuccession may, in fact, be executed substantially concurrently, or theblocks may sometimes be executed in the reverse order, depending uponthe functionality involved.

In some implementations, these computer program instructions may also bestored in a computer-readable memory that can direct a computer or otherprogrammable data processing apparatus to function in a particularmanner, such that the instructions stored in the computer-readablememory produce an article of manufacture including instruction meanswhich implement the function/act specified in the flowchart and/or blockdiagram block or blocks or combinations thereof.

In some implementations, the computer program instructions may also beloaded onto a computer or other programmable data processing apparatusto cause a series of operational steps to be performed (not necessarilyin a particular order) on the computer or other programmable apparatusto produce a computer implemented process such that the instructionswhich execute on the computer or other programmable apparatus providesteps for implementing the functions/acts (not necessarily in aparticular order) specified in the flowchart and/or block diagram blockor blocks or combinations thereof.

Referring now to the example implementation of FIG. 1, there is shownmapping process 10 that may reside on and may be executed by a computer(e.g., computer 12), which may be connected to a network (e.g., network14) (e.g., the internet or a local area network). Examples of computer12 (and/or one or more of the client electronic devices noted below) mayinclude, but are not limited to, a storage system (e.g., a NetworkAttached Storage (NAS) system, a Storage Area Network (SAN)), a personalcomputer(s), a laptop computer(s), mobile computing device(s), a servercomputer, a series of server computers, a mainframe computer(s), or acomputing cloud(s). As is known in the art, a SAN may include one ormore of the client electronic devices, including a RAID device and a NASsystem. In some implementations, each of the aforementioned may begenerally described as a computing device. In certain implementations, acomputing device may be a physical or virtual device. In manyimplementations, a computing device may be any device capable ofperforming operations, such as a dedicated processor, a portion of aprocessor, a virtual processor, a portion of a virtual processor,portion of a virtual device, or a virtual device. In someimplementations, a processor may be a physical processor or a virtualprocessor. In some implementations, a virtual processor may correspondto one or more parts of one or more physical processors. In someimplementations, the instructions/logic may be distributed and executedacross one or more processors, virtual or physical, to execute theinstructions/logic. Computer 12 may execute an operating system, forexample, but not limited to, Microsoft® Windows®; Mac® OS X®; Red Hat®Linux®, Windows® Mobile, Chrome OS, Blackberry OS, Fire OS, or a customoperating system. (Microsoft and Windows are registered trademarks ofMicrosoft Corporation in the United States, other countries or both; Macand OS X are registered trademarks of Apple Inc. in the United States,other countries or both; Red Hat is a registered trademark of Red HatCorporation in the United States, other countries or both; and Linux isa registered trademark of Linus Torvalds in the United States, othercountries or both).

In some implementations, as will be discussed below in greater detail,an mapping process, such as mapping process 10 of FIG. 1, may receive,at a computing device, an I/O request directed to a compressed dataportion of a storage system. It may be determined whether the I/Orequest includes one of a first portion of information and a secondportion of information. An address of the compressed data portion may beobtained via downward mapping if the I/O request includes the firstportion of information. The address of the compressed data portion maybe obtained via upward mapping if the I/O request includes the secondportion of information. The I/O request may be executed at thecompressed data portion.

In some implementations, the instruction sets and subroutines of mappingprocess 10, which may be stored on storage device, such as storagedevice 16, coupled to computer 12, may be executed by one or moreprocessors and one or more memory architectures included within computer12. In some implementations, storage device 16 may include but is notlimited to: a hard disk drive; all forms of flash memory storagedevices; a tape drive; an optical drive; a RAID array (or other array);a random access memory (RAM); a read-only memory (ROM); or combinationthereof. In some implementations, storage device 16 may be organized asan extent, an extent pool, a RAID extent (e.g., an example 4D+1P R5,where the RAID extent may include, e.g., five storage device extentsthat may be allocated from, e.g., five different storage devices), amapped RAID (e.g., a collection of RAID extents), or combinationthereof.

In some implementations, network 14 may be connected to one or moresecondary networks (e.g., network 18), examples of which may include butare not limited to: a local area network; a wide area network; or anintranet, for example.

In some implementations, computer 12 may include a data store, such as adatabase (e.g., relational database, object-oriented database,triplestore database, etc.) and may be located within any suitablememory location, such as storage device 16 coupled to computer 12. Insome implementations, data, metadata, information, etc. describedthroughout the present disclosure may be stored in the data store. Insome implementations, computer 12 may utilize any known databasemanagement system such as, but not limited to, DB2, in order to providemulti-user access to one or more databases, such as the above notedrelational database. In some implementations, the data store may also bea custom database, such as, for example, a flat file database or an XMLdatabase. In some implementations, any other form(s) of a data storagestructure and/or organization may also be used. In some implementations,mapping process 10 may be a component of the data store, a standaloneapplication that interfaces with the above noted data store and/or anapplet/application that is accessed via client applications 22, 24, 26,28. In some implementations, the above noted data store may be, in wholeor in part, distributed in a cloud computing topology. In this way,computer 12 and storage device 16 may refer to multiple devices, whichmay also be distributed throughout the network. An example cloudcomputing environment that may be used with the disclosure may includebut is not limited to, e.g., Elastic Cloud Storage (ECS™) from Dell EMC™of Hopkinton, Mass. In some implementations, other cloud computingenvironments may be used without departing from the scope of thedisclosure.

In some implementations, computer 12 may execute a storage managementapplication (e.g., storage management application 21), examples of whichmay include, but are not limited to, e.g., a storage system application,a cloud computing application, a data synchronization application, adata migration application, a garbage collection application, or otherapplication that allows for the implementation and/or management of datain a clustered (or non-clustered) environment (or the like). In someimplementations, mapping process 10 and/or storage managementapplication 21 may be accessed via one or more of client applications22, 24, 26, 28. In some implementations, mapping process 10 may be astandalone application, or may be an applet/application/script/extensionthat may interact with and/or be executed within storage managementapplication 21, a component of storage management application 21, and/orone or more of client applications 22, 24, 26, 28. In someimplementations, storage management application 21 may be a standaloneapplication, or may be an applet/application/script/extension that mayinteract with and/or be executed within mapping process 10, a componentof mapping process 10, and/or one or more of client applications 22, 24,26, 28. In some implementations, one or more of client applications 22,24, 26, 28 may be a standalone application, or may be anapplet/application/script/extension that may interact with and/or beexecuted within and/or be a component of mapping process 10 and/orstorage management application 21. Examples of client applications 22,24, 26, 28 may include, but are not limited to, e.g., a storage systemapplication, a cloud computing application, a data synchronizationapplication, a data migration application, a garbage collectionapplication, or other application that allows for the implementationand/or management of data in a clustered (or non-clustered) environment(or the like), a standard and/or mobile web browser, an emailapplication (e.g., an email client application), a textual and/or agraphical user interface, a customized web browser, a plugin, anApplication Programming Interface (API), or a custom application. Theinstruction sets and subroutines of client applications 22, 24, 26, 28,which may be stored on storage devices 30, 32, 34, 36, coupled to clientelectronic devices 38, 40, 42, 44, may be executed by one or moreprocessors and one or more memory architectures incorporated into clientelectronic devices 38, 40, 42, 44.

In some implementations, one or more of storage devices 30, 32, 34, 36,may include but are not limited to: hard disk drives; flash drives, tapedrives; optical drives; RAID arrays; random access memories (RAM); andread-only memories (ROM). Examples of client electronic devices 38, 40,42, 44 (and/or computer 12) may include, but are not limited to, apersonal computer (e.g., client electronic device 38), a laptop computer(e.g., client electronic device 40), a smart/data-enabled, cellularphone (e.g., client electronic device 42), a notebook computer (e.g.,client electronic device 44), a tablet, a server, a television, a smarttelevision, a media (e.g., video, photo, etc.) capturing device, and adedicated network device. Client electronic devices 38, 40, 42, 44 mayeach execute an operating system, examples of which may include but arenot limited to, Android™, Apple® iOS®, Mac® OS X®; Red Hat® Linux®,Windows® Mobile, Chrome OS, Blackberry OS, Fire OS, or a customoperating system.

In some implementations, one or more of client applications 22, 24, 26,28 may be configured to effectuate some or all of the functionality ofmapping process 10 (and vice versa). Accordingly, in someimplementations, mapping process 10 may be a purely server-sideapplication, a purely client-side application, or a hybridserver-side/client-side application that is cooperatively executed byone or more of client applications 22, 24, 26, 28 and/or mapping process10.

In some implementations, one or more of client applications 22, 24, 26,28 may be configured to effectuate some or all of the functionality ofstorage management application 21 (and vice versa). Accordingly, in someimplementations, storage management application 21 may be a purelyserver-side application, a purely client-side application, or a hybridserver-side/client-side application that is cooperatively executed byone or more of client applications 22, 24, 26, 28 and/or storagemanagement application 21. As one or more of client applications 22, 24,26, 28, mapping process 10, and storage management application 21, takensingly or in any combination, may effectuate some or all of the samefunctionality, any description of effectuating such functionality viaone or more of client applications 22, 24, 26, 28, mapping process 10,storage management application 21, or combination thereof, and anydescribed interaction(s) between one or more of client applications 22,24, 26, 28, mapping process 10, storage management application 21, orcombination thereof to effectuate such functionality, should be taken asan example only and not to limit the scope of the disclosure.

In some implementations, one or more of users 46, 48, 50, 52 may accesscomputer 12 and mapping process 10 (e.g., using one or more of clientelectronic devices 38, 40, 42, 44) directly through network 14 orthrough secondary network 18. Further, computer 12 may be connected tonetwork 14 through secondary network 18, as illustrated with phantomlink line 54. Mapping process 10 may include one or more userinterfaces, such as browsers and textual or graphical user interfaces,through which users 46, 48, 50, 52 may access mapping process 10.

In some implementations, the various client electronic devices may bedirectly or indirectly coupled to network 14 (or network 18). Forexample, client electronic device 38 is shown directly coupled tonetwork 14 via a hardwired network connection. Further, clientelectronic device 44 is shown directly coupled to network 18 via ahardwired network connection. Client electronic device 40 is shownwirelessly coupled to network 14 via wireless communication channel 56established between client electronic device 40 and wireless accesspoint (i.e., WAP) 58, which is shown directly coupled to network 14. WAP58 may be, for example, an IEEE 802.11a, 802.11b, 802.11g, 802.11n,802.11ac, Wi-Fi®, RFID, and/or Bluetooth™ (including Bluetooth™ LowEnergy) device that is capable of establishing wireless communicationchannel 56 between client electronic device 40 and WAP 58. Clientelectronic device 42 is shown wirelessly coupled to network 14 viawireless communication channel 60 established between client electronicdevice 42 and cellular network/bridge 62, which is shown by exampledirectly coupled to network 14.

In some implementations, some or all of the IEEE 802.11x specificationsmay use Ethernet protocol and carrier sense multiple access withcollision avoidance (i.e., CSMA/CA) for path sharing. The various802.11x specifications may use phase-shift keying (i.e., PSK) modulationor complementary code keying (i.e., CCK) modulation, for example.Bluetooth™ (including Bluetooth™ Low Energy) is a telecommunicationsindustry specification that allows, e.g., mobile phones, computers,smart phones, and other electronic devices to be interconnected using ashort-range wireless connection. Other forms of interconnection (e.g.,Near Field Communication (NFC)) may also be used.

In some implementations, the various client electronic devices may bedirectly or indirectly coupled to network 14 (or network 18). Forexample, client electronic device 38 is shown directly coupled tonetwork 14 via a hardwired network connection. Further, clientelectronic device 44 is shown directly coupled to network 18 via ahardwired network connection. Client electronic device 40 is shownwirelessly coupled to network 14 via wireless communication channel 56established between client electronic device 40 and wireless accesspoint (i.e., WAP) 58, which is shown directly coupled to network 14. WAP58 may be, for example, an IEEE 802.11a, 802.11b, 802.11g, 802.11n,802.11ac, Wi-Fi®, RFID, and/or Bluetooth™ (including Bluetooth™ LowEnergy) device that is capable of establishing wireless communicationchannel 56 between client electronic device 40 and WAP 58. Clientelectronic device 42 is shown wirelessly coupled to network 14 viawireless communication channel 60 established between client electronicdevice 42 and cellular network/bridge 62, which is shown by exampledirectly coupled to network 14.

In some implementations, some or all of the IEEE 802.11x specificationsmay use Ethernet protocol and carrier sense multiple access withcollision avoidance (i.e., CSMA/CA) for path sharing. The various802.11x specifications may use phase-shift keying (i.e., PSK) modulationor complementary code keying (i.e., CCK) modulation, for example.Bluetooth™ (including Bluetooth™ Low Energy) is a telecommunicationsindustry specification that allows, e.g., mobile phones, computers,smart phones, and other electronic devices to be interconnected using ashort-range wireless connection. Other forms of interconnection (e.g.,Near Field Communication (NFC)) may also be used.

In some implementations, various I/O requests (e.g., I/O request 15) maybe sent from, e.g., client applications 22, 24, 26, 28 to, e.g.,computer 12. Examples of I/O request 15 may include but are not limitedto, data write requests (e.g., a request that content be written tocomputer 12) and data read requests (e.g., a request that content beread from computer 12).

Data Storage System:

Referring also to the example implementation of FIGS. 2-3 (e.g., wherecomputer 12 may be configured as a data storage system), computer 12 mayinclude storage processor 100 and a plurality of storage targets (e.g.,storage targets 102, 104, 106, 108, 110). In some implementations,storage targets 102, 104, 106, 108, 110 may include any of theabove-noted storage devices. In some implementations, storage targets102, 104, 106, 108, 110 may be configured to provide various levels ofperformance and/or high availability. For example, storage targets 102,104, 106, 108, 110 may be configured to form a non-fully-duplicativefault-tolerant data storage system (such as a non-fully-duplicative RAIDdata storage system), examples of which may include but are not limitedto: RAID 3 arrays, RAID 4 arrays, RAID 5 arrays, and/or RAID 6 arrays.It will be appreciated that various other types of RAID arrays may beused without departing from the scope of the present disclosure.

While in this particular example, computer 12 is shown to include fivestorage targets (e.g., storage targets 102, 104, 106, 108, 110), this isfor example purposes only and is not intended limit the presentdisclosure. For instance, the actual number of storage targets may beincreased or decreased depending upon, e.g., the level ofredundancy/performance/capacity required.

Further, the storage targets (e.g., storage targets 102, 104, 106, 108,110) included with computer 12 may be configured to form a plurality ofdiscrete storage arrays. For instance, and assuming for example purposesonly that computer 12 includes, e.g., ten discrete storage targets, afirst five targets (of the ten storage targets) may be configured toform a first RAID array and a second five targets (of the ten storagetargets) may be configured to form a second RAID array.

In some implementations, one or more of storage targets 102, 104, 106,108, 110 may be configured to store coded data (e.g., via storagemanagement application 21), wherein such coded data may allow for theregeneration of data lost/corrupted on one or more of storage targets102, 104, 106, 108, 110. Examples of such coded data may include but isnot limited to parity data and Reed-Solomon data. Such coded data may bedistributed across all of storage targets 102, 104, 106, 108, 110 or maybe stored within a specific storage target.

Examples of storage targets 102, 104, 106, 108, 110 may include one ormore data arrays, wherein a combination of storage targets 102, 104,106, 108, 110 (and any processing/control systems associated withstorage management application 21) may form data array 112.

The manner in which computer 12 is implemented may vary depending upone.g., the level of redundancy/performance/capacity required. Forexample, computer 12 may be configured as a SAN (i.e., a Storage AreaNetwork), in which storage processor 100 may be, e.g., a dedicatedcomputing system and each of storage targets 102, 104, 106, 108, 110 maybe a RAID device. An example of storage processor 100 may include but isnot limited to a VPLEX™ system offered by Dell EMC™ of Hopkinton, Mass.

In the example where computer 12 is configured as a SAN, the variouscomponents of computer 12 (e.g., storage processor 100, and storagetargets 102, 104, 106, 108, 110) may be coupled using networkinfrastructure 114, examples of which may include but are not limited toan Ethernet (e.g., Layer 2 or Layer 3) network, a fiber channel network,an InfiniBand network, or any other circuit switched/packet switchednetwork.

As discussed above, various I/O requests (e.g., I/O request 15) may begenerated. For example, these I/O requests may be sent from, e.g.,client applications 22, 24, 26, 28 to, e.g., computer 12.Additionally/alternatively (e.g., when storage processor 100 isconfigured as an application server or otherwise), these I/O requestsmay be internally generated within storage processor 100 (e.g., viastorage management application 21). Examples of I/O request 15 mayinclude but are not limited to data write request 116 (e.g., a requestthat content 118 be written to computer 12) and data read request 120(e.g., a request that content 118 be read from computer 12).

In some implementations, during operation of storage processor 100,content 118 to be written to computer 12 may be received and/orprocessed by storage processor 100 (e.g., via storage managementapplication 21). Additionally/alternatively (e.g., when storageprocessor 100 is configured as an application server or otherwise),content 118 to be written to computer 12 may be internally generated bystorage processor 100 (e.g., via storage management application 21).

As discussed above, the instruction sets and subroutines of storagemanagement application 21, which may be stored on storage device 16included within computer 12, may be executed by one or more processorsand one or more memory architectures included with computer 12.Accordingly, in addition to being executed on storage processor 100,some or all of the instruction sets and subroutines of storagemanagement application 21 (and/or mapping process 10) may be executed byone or more processors and one or more memory architectures includedwith data array 112.

In some implementations, storage processor 100 may include front endcache memory system 122. Examples of front end cache memory system 122may include but are not limited to a volatile, solid-state, cache memorysystem (e.g., a dynamic RAM cache memory system), a non-volatile,solid-state, cache memory system (e.g., a flash-based, cache memorysystem), and/or any of the above-noted storage devices.

In some implementations, storage processor 100 may initially storecontent 118 within front end cache memory system 122. Depending upon themanner in which front end cache memory system 122 is configured, storageprocessor 100 (e.g., via storage management application 21) mayimmediately write content 118 to data array 112 (e.g., if front endcache memory system 122 is configured as a write-through cache) or maysubsequently write content 118 to data array 112 (e.g., if front endcache memory system 122 is configured as a write-back cache).

In some implementations, one or more of storage targets 102, 104, 106,108, 110 may include a backend cache memory system. Examples of thebackend cache memory system may include but are not limited to avolatile, solid-state, cache memory system (e.g., a dynamic RAM cachememory system), a non-volatile, solid-state, cache memory system (e.g.,a flash-based, cache memory system), and/or any of the above-notedstorage devices.

Storage Targets:

As discussed above, one or more of storage targets 102, 104, 106, 108,110 may be a RAID device. For instance, and referring also to FIG. 3,there is shown example target 150, wherein target 150 may be one exampleimplementation of a RAID implementation of, e.g., storage target 102,storage target 104, storage target 106, storage target 108, and/orstorage target 110. An example of target 150 may include but is notlimited to a VNX™ system offered by Dell EMC™ of Hopkinton, Mass.Examples of storage devices 154, 156, 158, 160, 162 may include one ormore electro-mechanical hard disk drives, one or more solid-state/flashdevices, and/or any of the above-noted storage devices.

In some implementations, target 150 may include storage processor 152and a plurality of storage devices (e.g., storage devices 154, 156, 158,160, 162). Storage devices 154, 156, 158, 160, 162 may be configured toprovide various levels of performance and/or high availability (e.g.,via storage management application 21). For example, one or more ofstorage devices 154, 156, 158, 160, 162 (or any of the above-notedstorage devices) may be configured as a RAID 0 array, in which data isstriped across storage devices. By striping data across a plurality ofstorage devices, improved performance may be realized. However, RAID 0arrays may not provide a level of high availability. Accordingly, one ormore of storage devices 154, 156, 158, 160, 162 (or any of theabove-noted storage devices) may be configured as a RAID 1 array, inwhich data is mirrored between storage devices. By mirroring databetween storage devices, a level of high availability may be achieved asmultiple copies of the data may be stored within storage devices 154,156, 158, 160, 162.

While storage devices 154, 156, 158, 160, 162 are discussed above asbeing configured in a RAID 0 or RAID 1 array, this is for examplepurposes only and not intended to limit the present disclosure, as otherconfigurations are possible. For example, storage devices 154, 156, 158,160, 162 may be configured as a RAID 3, RAID 4, RAID 5 or RAID 6 array.

While in this particular example, target 150 is shown to include fivestorage devices (e.g., storage devices 154, 156, 158, 160, 162), this isfor example purposes only and not intended to limit the presentdisclosure. For instance, the actual number of storage devices may beincreased or decreased depending upon, e.g., the level ofredundancy/performance/capacity required.

In some implementations, one or more of storage devices 154, 156, 158,160, 162 may be configured to store (e.g., via storage managementapplication 21) coded data, wherein such coded data may allow for theregeneration of data lost/corrupted on one or more of storage devices154, 156, 158, 160, 162. Examples of such coded data may include but arenot limited to parity data and Reed-Solomon data. Such coded data may bedistributed across all of storage devices 154, 156, 158, 160, 162 or maybe stored within a specific storage device.

The manner in which target 150 is implemented may vary depending upone.g., the level of redundancy/performance/capacity required. Forexample, target 150 may be a RAID device in which storage processor 152is a RAID controller card and storage devices 154, 156, 158, 160, 162are individual “hot-swappable” hard disk drives. Another example oftarget 150 may be a RAID system, examples of which may include but arenot limited to an NAS (i.e., Network Attached Storage) device or a SAN(i.e., Storage Area Network).

In some implementations, storage target 150 may execute all or a portionof storage management application 21. The instruction sets andsubroutines of storage management application 21, which may be stored ona storage device (e.g., storage device 164) coupled to storage processor152, may be executed by one or more processors and one or more memoryarchitectures included with storage processor 152. Storage device 164may include but is not limited to any of the above-noted storagedevices.

As discussed above, computer 12 may be configured as a SAN, whereinstorage processor 100 may be a dedicated computing system and each ofstorage targets 102, 104, 106, 108, 110 may be a RAID device.Accordingly, when storage processor 100 processes data requests 116,120, storage processor 100 (e.g., via storage management application 21)may provide the appropriate requests/content (e.g., write request 166,content 168 and read request 170) to, e.g., storage target 150 (which isrepresentative of storage targets 102, 104, 106, 108 and/or 110).

In some implementations, during operation of storage processor 152,content 168 to be written to target 150 may be processed by storageprocessor 152 (e.g., via storage management application 21). Storageprocessor 152 may include cache memory system 172. Examples of cachememory system 172 may include but are not limited to a volatile,solid-state, cache memory system (e.g., a dynamic RAM cache memorysystem) and/or a non-volatile, solid-state, cache memory system (e.g., aflash-based, cache memory system). During operation of storage processor152, content 168 to be written to target 150 may be received by storageprocessor 152 (e.g., via storage management application 21) andinitially stored (e.g., via storage management application 21) withinfront end cache memory system 172.

Referring also to the example implementation of FIG. 4, there is shown adiagrammatic view of an example file system layout 400. In someimplementations, storage management application 21 may implement anInline Compression (ILC) feature. ILC may provide the ability to reducethe amount of storage needed for user data on a storage device bycompressing portions of the data at the time the data is first written.To support this feature, at least in part, file system layout 400 mayinclude a ILC Virtual Block Metadata (VBM) and compressed data segmentto hold the compressed data. Each compressed data portion may beassociated with an extent stored in the Extent List inside the ILC VBM.To support recoverability of the ILC VBM, e.g., in the case when acyclic redundancy check (CRC) or other error detecting technique of theILC VBMs are all bad), there may be a ZipHeader in the beginning ofevery compressed data portion.

As will be discussed below, mapping process 10 may at least help, e.g.,improvement data storage technology, necessarily rooted in computertechnology in order to overcome an example and non-limiting problemspecifically arising in the realm of storage systems associated with,e.g., upward and downward mapping of volume data block/file data blockdata, not only for non-compressed data blocks, but also for compresseddata blocks.

The Mapping Process:

As discussed above and referring also at least to the exampleimplementations of FIGS. 5-7, mapping process 10 may receive 500, at acomputing device, an I/O request directed to a compressed data portionof a storage system. Mapping process 10 may determine 502 whether theI/O request includes one of a first portion of information and a secondportion of information. Mapping process 10 may obtain 504 an address ofthe compressed data portion via downward mapping if the I/O requestincludes the first portion of information. Mapping process 10 may obtain506 the address of the compressed data portion via upward mapping if theI/O request includes the second portion of information. Mapping process10 may execute 508 the I/O request at the compressed data portion.

In some implementations, mapping process 10 may receive 500, at acomputing device, an I/O request directed to a compressed data portionof a storage system. For instance, assume for example purposes only thata user (e.g., user 46) has sent an I/O (e.g., I/O request 15) directedto the compressed data portion shown in the example storage systemlayout 600 of FIG. 6, and example storage system layout 700 of FIG. 7.In the example, I/O request 15 may be received 500 by mapping process10.

In some implementations, mapping process 10 may determine 502 whetherthe I/O request includes one of a first portion of information and asecond portion of information. For instance, and referring at least tothe example implementation of FIG. 6, an example storage system layout600 is shown. In some implementations, the first portion of informationmay include a file system ID (e.g., file system ID 602), an inode number(e.g., inode number 604), and a file block offset (e.g., file blockoffset 606). Thus, in the example, mapping process 10 may receive 500 anI/O request (e.g., I/O request 15), and may analyze the content of theI/O request to determine 502 if the I/O request includes file system ID602, inode number 604, and file block offset 606 associated with, e.g.,file system 608.

In some implementations, the second portion of information may includean address of a compressed data block (e.g., DB#1 associated withcompressed data 610) in a data volume (e.g., data volume 612). Thus, inthe example, as will be discussed below, mapping process 10 may receive500 an I/O request (e.g., I/O request 15), and may analyze the contentof the I/O request to determine 502 if the I/O request includes anaddress of a compressed data block DB#1 associated with, e.g., datavolume 612.

In some implementations, mapping process 10 may obtain 504 an address ofthe compressed data portion via downward mapping if the I/O requestincludes the first portion of information. For instance, assume forexample purposes only that the received 500 I/O request includes filesystem ID 602, inode number 604, and file block offset 606. Given, thisinformation, mapping process 10 may obtain 504 the address (e.g.,location) of either the compressed data block or non-compressed datablock stored in the data volume. For example, assume the followingexample information is provided in I/O request 15 (e.g., Input: inode1,file_inode_num=9427, file_block_offset=64K bytes). In the example, andin some implementations, obtaining 504 the address of the compresseddata portion via downward mapping may include locating 510 a mappingpointer that points to compression Virtual Block Metadata, wherein thecompression Virtual Block Metadata may include a ZipHeader with aplurality of file offsets. For instance, mapping process 10 may read theinode structure (e.g., of inode1), and look through each level of IBs(indirect blocks) by file block offset. For example, mapping process 10may locate 510 the mapping pointer (MP) by reading the data structure ofthe inode (e.g., inode 9427) from file system 608. In the example, thefile block offset of, e.g., 64K is the No. 8 data block (e.g., whenusing 8K per data block). In the example, mapping process 10 may readthe No. 8 MP from the inode structure, where the No. 8 MP stores theaddress of the compression Virtual Block Metadata (e.g., CVBM (e.g.,0x472)).

Continuing with the above example, mapping process 10 may obtain the MP(e.g., MP 702) that points to the CVBM, where the compressed data may bestored in the compressed region to which the CVBM points, and where eachcompressed data may have a ZipHeader (ZipH) with different file offsets.In some implementations, mapping process 10 may read the data structureof CVBM (e.g., 0x472) from file system 608, where the CVBM's MP value(e.g., 0x10040) is the address (in blocks) of the compressed regionwithin data volume 612.

In some implementations, obtaining 504 the address of the compresseddata portion via downward mapping may further include obtaining 512 atleast one file offset of the plurality of file offsets, and at least onebyte offset. For example, mapping process 10 may obtain 512 the fileoffset and byte offset by reading the CVBM structure (e.g., CVBMstructure 704), which may store the file offset and byte offset (e.g.,within the compressed region) for each compressed data.

In some implementations, mapping process 10 may obtain the address ofcompressed region 610 from CVBM structure 704 and may obtain the addressof compressed data within the compressed region by searching the fileoffset in CVBM structure 704. For instance, assume for example purposesonly that CVBM structure 704 has 4 extents, with a file offset value ofextent#2 being, e.g., 64K, which is the same as the file block offset.Thus, in the example, extent#2 is mapping to the compressed data that isultimately referenced by I/O request 15.

In some implementations, the length value of extent#2 (e.g., 0x8) may bethe length of compressed data in sectors. In the example, the offset ofcompressed data within the compressed region may be sum of the length ofall its previous compressed data, e.g., the length of extent#1 (e.g.,0x4). As each block (e.g., 8 KB) may have 16 sectors (e.g., 512B), theaddress of compressed data in this example may be:0x10040*16+0x4=0x100404 sectors (or 0x20080800 bytes). With the aboveaddress information, mapping process 10 may obtain 504 the address ofthe compressed data in the data volume ultimately referenced by I/Orequest 15, with the example final output as follows:

compressed_data_address=0x100404 sectors or 0x20080800 bytes

compressed_data_length=0x8 sectors or 4096 bytes

In some implementations, mapping process 10 may obtain 506 the addressof the compressed data portion via upward mapping if the I/O requestincludes the second portion of information. For instance, as notedabove, the second portion of information may include an address of acompressed data block (e.g., DB#1 associated with compressed data 610)in a data volume (e.g., data volume 612). Assume for example purposesonly that the received 500 I/O request includes the address of thecompressed data block in data volume 612. Given, this information,mapping process 10 may obtain 506 the address (e.g., location) of eitherthe compressed data block or non-compressed data block stored in thedata volume (e.g., via the file system ID and inode number of the filethat holds the compressed data and its block offset within the file).For example, assume the following example information is provided in I/Orequest 15 (e.g., Input: compressed_data_address=0x100404 sectors). Insome implementations, there may be multiple files (e.g., inode files)that hold the compressed data due to file snapshot technology, thus,mapping process 10 may eventually output multiple pairs of (inodenumber, file offset).

In some implementations, obtaining 506 the address of the compresseddata portion via upward mapping may include obtaining 514 a compressionVirtual Block Metadata address from a block metadata in which thecompressed data portion resides. For example, mapping process 10 mayobtain 514 the CVBM address by reading the block metadata (BMD), such asBMD 706, of the block in which the compressed data resides, as the BMDmay contain the CVBM address. In the example, sector #0x100404 residesin block #0x10040 (e.g., when using 16 sectors per block). In someimplementations, every data block may have a BMD, which in the examplemay be read from the BMD of block#0x10040. In some implementations, BMD706 may contain an MP (e.g., 0x472) pointing to CVBM 704.

In some implementations, obtaining 506 the address of the compresseddata portion via upward mapping may further include verifying 516 amapping to the compressed data portion using an inode number and fileblock offset pair. For instance, mapping process 10 may read CVBMstructure 704 to obtain the address of the compressed region, and thenmay obtain the offset of the compressed data within the compressed dataregion. For example, mapping process 10 may read the data structure ofCVBM 704 (e.g., 0x472) from file system 608. In the example, the CVBM'sMP value (e.g., 0x10040) is the address of the compressed region withindata volume 612.

In the example, by searching the above-noted offset obtained via theaddress of the compressed region (located by reading the CVBM), mappingprocess 10 may obtain the file offset of the compressed data. In theexample, the address of the compressed data is 0x100404 sectors, so theoffset of the compressed data within the compressed region is 4 sectors(e.g., 0x100404-0x10040*16). Continuing with the example, mappingprocess 10 may read the version set ID from CVBM 704, and may obtain acollection of inode numbers from a version set db (e.g., version set db708). In some implementations, for each inode number, mapping process 10may (as noted above for downward mapping) read the inode structure(e.g., of inode1), and look through each level of IBs (indirect blocks)by file block offset and obtain the MP (e.g., MP 702) that points to theCVBM. In the example, mapping process 10 may look into 4 extents in theCVBM, as first extent's length is, e.g., 4 sectors, so the second extentis mapping to the compressed data (e.g., 0x100404). In the example, thesecond extent's file offset (e.g., 64K) is the offset of the data withinthe file. The value of the VersionSetID in CVBM 704 may be the identityof the version set, which may be a group of inode numbers of the fileand all its snaps. By searching the VersionSetDB (e.g., stored in filesystem 608) with the VersionSetID, mapping process 10 may obtain threeinode numbers: e.g., 9426, 9427, and 9428. In the example, all three ofthese inodes may possibly contain the compressed data ultimatelyreferenced by I/O request 15, and as such, mapping process 10 may verify516 them one by one.

For example, if the CVBM address is the same as the CVBM addressobtained by reading the MBD of the block in which the compressed dataresides, the pair (inode number, file block offset) is mapping to thecompressed data block. In the example, mapping process 10 may read thedata structure of the inode (e.g., 9426), and since mapping process 10has already obtained the file offset (e.g., 64K) as discussed above,mapping process 10 may read the No. 8 MP from the inode structure.

In the example, the address in the No. 8 MP (e.g., 0x471) is not equalto the CVBM address (e.g., 0x472), thus, inode 9426 does not contain thecompressed data referenced in I/O request 15. Mapping process 10 mayread the data structure of the next inode (e.g., 9427) by reading theNo. 8 MP from the inode structure. In the example, the address in theNo. 8 MP (e.g., 0x472) is equal to the CVBM address (e.g., 0x472), thus,inode 9427 does contain the compressed data referenced in I/O request15. Mapping process 10 may read the data structure of the next inode(e.g., 9428) by reading the No. 8 MP from the inode structure. In theexample, the address in the No. 8 MP (e.g., 0x472) is equal to the CVBMaddress (e.g., 0x472), thus, inode 9428 does contain the compressed datareferenced in I/O request 15. Thus, mapping process 10 may obtain 506the address of the compressed data in the data volume ultimatelyreferenced by I/O request 15, where there are, e.g., two file datablocks mapping to the compressed data, with the example final outputs asfollows:

file_inode_num=9427, file_block_offset=64K bytes

file_inode_num=9428, file_block_offset=64K bytes

In some implementations, mapping process 10 may execute 508 the I/Orequest at the compressed data portion. For example, by obtaining504/506 the address of the compressed data in the data volume ultimatelyreferenced by I/O request 15 via downward/upward mapping, the dataultimately referenced by I/O request 15 (e.g., read/write) may beexecuted.

In some implementations, mapping process 10 may be used, e.g., totroubleshoot DMC issues related to an (inline) compression feature. Forinstance, when DMC happens, DMC detection software (which may beincluded as part of mapping process 10) may give the location of themis-compared data in the file system layer. By utilizing mapping process10, a DMC auto-analyzer may be able to find the location of mis-comparedcompressed data in the data volume layer. Additionally, as anotherexample, when a corrupted compressed data block is detected, mappingprocess 10 may find some or all of the affected files, and mayrecover/restore those specific files (e.g., from a backup system).

The terminology used herein is for the purpose of describing particularimplementations only and is not intended to be limiting of thedisclosure. As used herein, the singular forms “a”, “an” and “the” areintended to include the plural forms as well, unless the context clearlyindicates otherwise. As used herein, the language “at least one of A, B,and C” (and the like) should be interpreted as covering only A, only B,only C, or any combination of the three, unless the context clearlyindicates otherwise. It will be further understood that the terms“comprises” and/or “comprising,” when used in this specification,specify the presence of stated features, integers, steps (notnecessarily in a particular order), operations, elements, and/orcomponents, but do not preclude the presence or addition of one or moreother features, integers, steps (not necessarily in a particular order),operations, elements, components, and/or groups thereof.

The corresponding structures, materials, acts, and equivalents (e.g., ofall means or step plus function elements) that may be in the claimsbelow are intended to include any structure, material, or act forperforming the function in combination with other claimed elements asspecifically claimed. The description of the present disclosure has beenpresented for purposes of illustration and description, but is notintended to be exhaustive or limited to the disclosure in the formdisclosed. Many modifications, variations, substitutions, and anycombinations thereof will be apparent to those of ordinary skill in theart without departing from the scope and spirit of the disclosure. Theimplementation(s) were chosen and described in order to explain theprinciples of the disclosure and the practical application, and toenable others of ordinary skill in the art to understand the disclosurefor various implementation(s) with various modifications and/or anycombinations of implementation(s) as are suited to the particular usecontemplated.

Having thus described the disclosure of the present application indetail and by reference to implementation(s) thereof, it will beapparent that modifications, variations, and any combinations ofimplementation(s) (including any modifications, variations,substitutions, and combinations thereof) are possible without departingfrom the scope of the disclosure defined in the appended claims.

What is claimed is:
 1. A computer-implemented method comprising:receiving, at a computing device, an I/O request directed to acompressed data portion of a storage system; determining whether the I/Orequest includes one of a first portion of information and a secondportion of information; obtaining an address of the compressed dataportion via downward mapping if the I/O request includes the firstportion of information; obtaining the address of the compressed dataportion via upward mapping if the I/O request includes the secondportion of information; and executing the I/O request at the compresseddata portion.
 2. The computer-implemented method of claim 1 wherein thefirst portion of information includes a file system ID, an inode number,and a file block offset.
 3. The computer-implemented method of claim 2wherein obtaining the address of the compressed data portion viadownward mapping includes locating a mapping pointer that points tocompression Virtual Block Metadata, wherein the compression VirtualBlock Metadata includes a ZipHeader with a plurality of file offsets. 4.The computer-implemented method of claim 3 wherein obtaining the addressof the compressed data portion via downward mapping further includesobtaining at least one file offset of the plurality of file offsets, andat least one byte offset.
 5. The computer-implemented method of claim 1wherein the second portion of information includes an address of acompressed data block in a data volume.
 6. The computer-implementedmethod of claim 5 wherein obtaining the address of the compressed dataportion via upward mapping includes obtaining a compression VirtualBlock Metadata address from a block metadata in which the compresseddata portion resides.
 7. The computer-implemented method of claim 6wherein obtaining the address of the compressed data portion via upwardmapping further includes verifying a mapping to the compressed dataportion using an inode number and file block offset pair.
 8. A computerprogram product residing on a non-transitory computer readable storagemedium having a plurality of instructions stored thereon which, whenexecuted across one or more processors, causes at least a portion of theone or more processors to perform operations comprising: receiving anI/O request directed to a compressed data portion of a storage system;determining whether the I/O request includes one of a first portion ofinformation and a second portion of information; obtaining an address ofthe compressed data portion via downward mapping if the I/O requestincludes the first portion of information; obtaining the address of thecompressed data portion via upward mapping if the I/O request includesthe second portion of information; and executing the I/O request at thecompressed data portion.
 9. The computer program product of claim 8wherein the first portion of information includes a file system ID, aninode number, and a file block offset.
 10. The computer program productof claim 9 wherein obtaining the address of the compressed data portionvia downward mapping includes locating a mapping pointer that points tocompression Virtual Block Metadata, wherein the compression VirtualBlock Metadata includes a ZipHeader with a plurality of file offsets.11. The computer program product of claim 10 wherein obtaining theaddress of the compressed data portion via downward mapping furtherincludes obtaining at least one file offset of the plurality of fileoffsets, and at least one byte offset.
 12. The computer program productof claim 8 wherein the second portion of information includes an addressof a compressed data block in a data volume.
 13. The computer programproduct of claim 12 wherein obtaining the address of the compressed dataportion via upward mapping includes obtaining a compression VirtualBlock Metadata address from a block metadata in which the compresseddata portion resides.
 14. The computer program product of claim 13wherein obtaining the address of the compressed data portion via upwardmapping further includes verifying a mapping to the compressed dataportion using an inode number and file block offset pair.
 15. Acomputing system including one or more processors and one or morememories configured to perform operations comprising: receiving an I/Orequest directed to a compressed data portion of a storage system;determining whether the I/O request includes one of a first portion ofinformation and a second portion of information; obtaining an address ofthe compressed data portion via downward mapping if the I/O requestincludes the first portion of information; obtaining the address of thecompressed data portion via upward mapping if the I/O request includesthe second portion of information; and executing the I/O request at thecompressed data portion.
 16. The computing system of claim 15 whereinthe first portion of information includes a file system ID, an inodenumber, and a file block offset.
 17. The computing system of claim 16wherein obtaining the address of the compressed data portion viadownward mapping includes locating a mapping pointer that points tocompression Virtual Block Metadata, wherein the compression VirtualBlock Metadata includes a ZipHeader with a plurality of file offsets.18. The computing system of claim 17 wherein obtaining the address ofthe compressed data portion via downward mapping further includesobtaining at least one file offset of the plurality of file offsets, andat least one byte offset.
 19. The computing system of claim 15 whereinthe second portion of information includes an address of a compresseddata block in a data volume.
 20. The computing system of claim 19wherein obtaining the address of the compressed data portion via upwardmapping includes obtaining a compression Virtual Block Metadata addressfrom a block metadata in which the compressed data portion resides andverifying a mapping to the compressed data portion using an inode numberand file block offset pair.